The invention provides an annular nuclear fuel partition cooling dual-mode space nuclear reactor and a spacecraft. The reactor is characterized in that the reactor comprises an outer pressure vessel shell, an inner annular shell (10) and a spray pipe (9), annular nuclear fuel is placed in the inner annular shell (10) to form an independent annular nuclear fuel internal flow channel (7) and an independent annular nuclear fuel external space (3), and the annular nuclear fuel internal flow channel (7) and the independent annular nuclear fuel external space (3) are used for forming a cooling working medium circulation loop; a coolant for the nuclear heat propulsion mode enters the reactor core from a nuclear heat inlet pipe (5) at the upper part of the reactor, flows through the reactor core through an annular nuclear fuel internal flow channel (7), and is directly sprayed out from a spray pipe (9) at the bottom of the reactor core to generate thrust, and the coolant for the nuclear power propulsion mode flows in from a nuclear power inlet pipe (1) at the upper part of the reactor core. According to the invention, the problem of dual-mode joint work or time-sharing work of nuclear heat propulsion and nuclear power propulsion is solved, dual-mode simultaneous work can be realized in a limited space, and only one mode can be used at the same time, so that the flexibility is improved, and the cost is reduced.

本发明提供了一种环形核燃料分区冷却双模式空间核反应堆以及航天器。反应堆的特征在于，其包括外压力容器壳体、内环形壳体(10)、和喷管(9)，环形核燃料放置在内环形壳体(10)内形成独立的环形核燃料内部流道(7)和环形核燃料外部空间(3)用于形成冷却工质循环回路，核热推进模式用冷却剂由反应堆上部核热入口管(5)进入堆芯，经环形核燃料内部流道(7)流过堆芯，自堆芯底部的喷管(9)直接喷出产生推力，核电推进模式用冷却剂自堆芯上部的核电入口管(1)流入。本发明解决了核热推进、核电推进双模式共同工作或分时工作的问题，可实现在有限空间内既实现双模式同时工作，又可同时仅使用一种模式，提高了灵活性，降低了成本。